Family planning services (including contraception and infertility services) and abortion services are delivered in a variety of settings, primarily by obstetrician-gynecologists. There is considerable evidence that physicians' attitudes toward these services and toward women clients, as well as their practice decisions, influence the volume and nature of fertility-control services delivered to women, the settings in which these services are delivered, and their accessibility to adolescents, the poor, and minorities. With growing levels of teenage pregnancy and current threats to the provision of family planning and abortion services, the role of providers as "gate-keepers" in the fertility-control services delivery system is likely to become an increasingly important determinant of fertility regulation among women. This study will investigate the implications of the changing sex composition of obstetrics-gynecology for the delivery of fertility-control services to women. Since 1974, the proportional representation of women physicians in obstetrics-gynecology has grown: women are now 33% of all residents in the specialty and will soon be 20% of practicing obstetrician-gynecologists, up from 9% previously. Women may be more sensitive providers of fertility-control services, extending their accessibility to more women and improving clients' effective use of such services. A cross-sectional national survey combining telephone interviews and mailed questionnaires will be conducted using a stratified random sample of male and female physicians who recently completed residencies in obstetrics-gynecology. The American College of Obstetricians and Gynecologists will assist in selecting a sample of about 2,000 physicians, 50% of whom are women. Analysis will focus on the relative influences of gender, practice settings, and professional socialization on both attitudes toward and delivery of specific fertility-control services to various types of patients. Findings will permit us to anticipate changes in the volume, distribution, and nature of fertility-control services to women as a consequence of the increasing proportion of women providers.